Man japan and their dense as f*ck mc. Living for 15 years should've been enough for him to know the world's common sense. Its not like the family prevents him to go out and he has his brother and probably other people to talk to.
Hmm
Although it has some of the usual "trashy isekai" aspect, but it starts to grow better.
I hold some expectation to this manga. I hope it will not betrayed.